1. Field of Invention
This invention relates to power factor correction for induction motors and specifically to regulate input power as a function of the mechanical lead.
2. General Description of Prior Art
The induction motor is perhaps the most durable and most commonly used motor. The RPM of the motor runs at a basically constant speed which with in certain limits is independent of the mechanical lead and line voltage. The line voltage is given and is not controllable by the end user. The induction motor through design and specification considers the lowest line voltage for the given mechanical lead. The mechanical lead is variable which requires adjustments of the line voltage for optimum operation of the applied voltage and should be a function of the mechanical lead.
Various attempts have been made to address the aforementioned issues:
U.S. Pat. No. 4,052,648 Inventor Frank J. Nola--This patent addresses the motor input voltage control issue. Nola through circuit design controls the current angle flow cutting out a portion of the sinusoidal motor current once every half period of the 60 cycle line input. The resulting wave form is a distorted sinusoid producing multiple harmonics of the line frequency and high levels of electro magnetic pollution which is transmitted back through utility power lines contaminating the utility system resulting in an undesirable outcome. PA1 U.S. Pat. No. 4,459,528 Inventor Frank J. Nola--This patent addresses the same issues as were addressed in Pat. No.4,052,648 for the three phase induction motors having the same outcome. PA1 U.S. Pat. Nos. 4,433,276 Inventor Frank J. Nola--This patent addresses the same issues as sited in U.S. Pat. No. 4,052,648 and 4,459,528 however this patent extends the usage to three phase delta motors having the same inherent outcome.--U.S. Pat. No. 4,454,462 Inventor Robert J. Spann--This patent addresses the same issues as sited in Pat. Nos. 4,052.648, 4,459,528 and 4,433,276 however a different sensing method is used. The same inherent outcome results as sited in the Nola patents.